American Chemical Society
jz2c03817_si_001.pdf (2.02 MB)

Structural Bistability in RbI Monolayers on Ag(111)

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journal contribution
posted on 2023-03-22, 22:14 authored by Benjamin W. McDowell, Jon M. Mills, Motoaki Honda, George V. Nazin
Alkali halides are well-known for their tendency to form rock-salt-like crystal structures. Here we present a scanning tunneling microscopy study of a previously unreported alternative structure of one such alkali halide, RbI. When deposited on Ag(111) at a low submonolayer surface coverage, RbI forms islands with hexagonally coordinated atomic structures, in contrast to the expected rock-salt structures typically observed for such alkali halide films on metal surfaces. At a near-monolayer RbI surface coverage, we observe the coexistence of the hexagonally coordinated phase and a square-coordinated rock-salt-like RbI phase that is analogous to that observed for other alkali halides. Our density functional theory calculations for this system highlight the role of RbI–Ag interfacial charge transfer in defining the RbI structure and the impact of local atomic coordination on the RbI–Ag charge-transfer interaction.